It's pretty much impossible to have amps that are too powerful. However, the "first watt" idea is that the initial tone of any amp is where the truth is, not necessarily in its ability to arc weld, thus the less powerful but great sounding amp triumphs sonically...or the extremely powerful great sounding amp...or mid powered, although unpowered amps should be avoided as no sound will be forthcoming...and is that even an amp? (rhetorical question) Also, upgrades to the drivers (and maybe crossovers) in your Heresy speakers might be a great thing, or simply buy the newest version...that's what I did and they're amazing with my 12 watt per side single ended amp. Amazing.
